1. Field of the Invention
The present invention relates to a defect inspecting device for a substrate to be processed in a semiconductor manufacturing process, and in particular, to a device used in a positioning device for a substrate and a method of manufacturing a semiconductor device.
2. Description of the Related Art
In general, a semiconductor manufacturing process includes a plurality of processes and processes a wafer as a substrate to be processed by the plurality of processes to manufacture a semiconductor device (H semiconductor chip). In this semiconductor manufacturing process, it is necessary to preclude the misalignment of the wafer so as to prevent or suppress a defect occurred in the course of processing and transfer. For this reason, there has been used a positioning device for positioning the wafer with high accuracy.
FIG. 8 is a block diagram showing a conventional positioning device.
Referring to FIG. 8, a reference numeral 1 denotes a wafer as a substrate to be processed; a reference numeral 2 a vacuum holding base; a reference numeral 3 a cylinder; a reference numeral 4 an actuator; a reference numeral 5 an alignment member; a reference numeral 6 a transmission sensor; and a reference numeral 7 a control unit. The alignment member 5 is provided with the first flat plane 5a with the first radius, a slope 5b inclined upward at a predetermined angle from the peripheral of the first flat plane 5a, and a second flat plane 5c extending outward in the radial direction of the top end of the slop 5b and with the second radius. The first radius is equal to the second ones. The control unit 7 drives and controls the actuator 4 and the transmission sensor 6 in response to a control signal given by the control unit of a semiconductor production equipment (hereinafter referred to as a main control unit (not shown)). Then, the cylinder 3 is driven in the vertical direction within a range (moving range) predetermined by the actuator 4. Further, the cylinder 3 is rotated by the actuator 4. Thereby, the vacuum holding base 2 is moved in the vertical direction within a range predetermined by the first flat plane 5a and the second flat plane 5c and, at the same time, is rotated by taking the cylinder 3 as the axis of rotation. The wafer 1 is formed in a circle, for example, and a notch 111 is previously formed on the rim of the wafer 1. The notch 111 is devoted to positional detection.
Next, the operation of the conventional positioning device will be described.
The semiconductor production equipment (not shown) is provided with a carrier robot (not shown) and the wafer 1 is transferred by the carrier robot to the vacuum holding base 2 and is placed on the vacuum holding base 2, with its main plane (top surface) abutted against the vacuum holding base 2. In the case where the wafer 1 is placed on the vacuum holding base 2, when the cylinder 3 is moved to the uppermost position within the moving range, that is, when the vacuum holding base 2 is positioned at the uppermost position, the wafer 1 is placed on the vacuum holding base 2 by the carrier robot. At this time, the surface of the wafer 1 is a little lower than the second flat plane 5c. 
After the wafer 1 is placed on the vacuum holding base 2 in this manner, the cylinder 3 is moved in the vertical direction in FIG. 8 by the actuator 4 and then the vacuum holding base 2, that is, the wafer 1 is lowered. When the vacuum holding base 2 is lowered, the rim of the wafer 1 is lowered along the slope 5b and the top surface of the vacuum holding base 2 reaches the first flat plane 5a, the rim of the wafer 1 is positioned at the peripheral of the first flat plane 5a; that is, the wafer is centered.
Then, the wafer 1 is vacuum absorbed by the vacuum holding base 2 and then the cylinder 3 is moved upward by the actuator 4 to move up the vacuum holding base 2, that is, the wafer 1. Thereafter, the cylinder 3 is rotated by the actuator 4 to rotate the vacuum holding base 2, that is, the wafer 1 in the direction shown by an arrow in FIG. 8 by taking the cylinder 3 as the axis of rotation.
The transmission sensor 6 has a light projecting part 6a and a light receiving part 6b and, as shown in FIG. 8, the light projecting part 6a is opposed to the light receiving part 6b across the peripheral of the wafer 1. The control unit 7 drives the light projecting part 6a to emit light. As described above, the wafer 1 has the notch 111, so that when the notch 111 reaches a position where the transmission sensor 6 is arranged, the light emitted from the light projecting part 6a passes through the notch 111 and is received by the light receiving part 6b. That is to say, the wafer 1 is rotated until the light emitted from the light projecting part 6a is received by the light receiving part 6b to adjust the angle of the wafer 1. In other words, the control unit 7 rotates the wafer 1 until the notch 111 is detected by the transmission sensor 6 to adjust the angle of the wafer 1 (position of the wafer 1).
The angle (position) of the wafer 1 is adjusted in this manner and then the wafer 1 is received by the carrier robot and is transferred to a processing unit (processing chamber) attached to the semiconductor production equipment.
In the processing and the transfer processes of the wafer 1, as described above, it is necessary to position the wafer 1 and to inspect a defect on the wafer 1 such as a foreign matter adhered thereto and a crack (chip at the end of the wafer 1). In Japanese Patent Unexamined Publication No. 9-186209 (hereinafter referred to as a first prior art 1), there is disclosed a device (inspection device) for inspecting a defect on a wafer. In the first prior art, a wafer positioning unit is provided with a macro-inspecting function and when the wafer is positioned by detecting a positioning notch formed on the rim of the wafer, the wafer is slanted and vibrated to perform a macro observation. Further, in Japanese Patent Unexamined Publication No. 11-326229, there is disclosed a device in which a defect on a wafer is inspected when the wafer is positioned on an inspection stage with high accuracy (hereinafter referred to as a second prior art). That is to say, in the second prior art, a laser beam is irradiated on the inspection region (foreign matter detecting region) on the wafer and the upper scattered light is received by a detection optical system provided above in the vertical direction of an inspection table to detect a foreign matter. At this time, the coordinates of the center of the wafer are calculated and the calculated coordinates of the center are taken as the coordinates of the center of the wafer when the foreign matter is detected.
Further, in Japanese Patent Unexamined Publication No. 5-160245 (hereinafter referred to as a third prior art), there is disclosed a device for positioning a wafer and detecting a defect on the rim of the wafer. In the third prior art, the device includes a first rotary stage slightly rotatable nearly around the origin of an orthogonal coordinate system, a direct-moving stage mounted on the first rotary stage and two-dimensionally movable in the orthogonal coordinate system, and a second rotary stage mounted on the direct-moving stage and rotatable one rotation or more while holding the wafer. While the second rotary stage is rotating, the defect (chip or the like) on the rim of the wafer is detected by output information from the first detector for detecting information indicative of the change of displacement of the rim of the wafer from the center of rotation on a non-contact base.
In addition, in Japanese Patent Unexamined Publication No. 8-264606 (hereinafter referred to as a fourth prior art), there is disclosed a device for positioning a wafer on an X-Y stage in inspecting a foreign matter on the wafer. In the fourth prior art, the alignment of the wafer is checked by an observation-alignment optical system. Further, a foreign matter detected by the observation-alignment optical system is visually checked and depending on the observation results of the shape of the detected foreign matter, the pass or fail of the wafer is determined.
The conventional defect inspecting device for a substrate to be processed is constituted in the above manner. Even though, in any one of the prior arts 1 to 4, the wafer is inspected when positioning the wader, only the existence of the foreign matter is detected visually or by the detection optical system. Hence, it is impossible to inspect a defect such as a foreign matter or a chip on the wafer as to what shape it has or where it is. In order to make such an inspection, it has to inspect the wafers on which the existence of the defect is identified one by one in detail, for example, under a microscope.
In this manner, the conventional defect inspecting device for a substrate to be processed involves a problem that it is difficult to detect a defect on the wafer with high accuracy in positioning the wafer.
The present invention has been made to solve the above problems. It is an object of the present invention to provide a defect inspecting device for a substrate to be processed, capable of detecting a defect on a wafer, as a substrate to be processed, with high accuracy in positioning the wafer, and a method for inspecting a defect on a substrate to be processed.
It is another object of the present invention to provide a defect inspecting device for a substrate to be processed, capable of eliminating the need for inspecting a defect on a wafer visually or microscopically or the like and easily detecting the abnormality of the wafer, and a method for inspecting a defect on a substrate to be processed.
It is still another object of the present invention to provide a semiconductor device capable of improving productivity of a semiconductor device by the above-mentioned device for inspecting a defect on a substrate to be processed.
A defect inspecting device for a substrate to be processed according to the present invention is built in a positioning device for positioning a substrate in a semiconductor manufacturing process and includes an inspection unit for inspecting a defect on the substrate, after the substrate is positioned, while rotating the substrate at least one rotation from a position where the substrate is positioned, and an angle information calculating means for finding a defective position, when a defect is detected on the substrate, as angle information indicative of the angle of rotation of the substrate.
A method for manufacturing a semiconductor device having a defect inspecting device for a substrate to be processed according to the present invention is built in a positioning device for positioning the substrate in a semiconductor manufacturing process and includes inspecting means for inspecting a defect on the substrate, after the substrate is positioned, while rotating the substrate at least one rotation from the position where the substrate is positioned, the method including the step of removing the substrate from a semiconductor manufacturing process when the inspection means judges the substrate to be defective.
A method for manufacturing a semiconductor device having a defect inspecting device for a substrate to be processed according to the present invention is built in a positioning device for positioning the substrate in a semiconductor manufacturing process and includes inspecting means for inspecting a defect on the substrate, after the substrate is positioned, while rotating the substrate at least one rotation from a position where the substrate is positioned, said inspecting means including judging means for judging that a defect is detected on the substrate when the intensity of the scattered light exceeds a predetermined threshold and sending an alarm signal, the method including the step of raising an alarm upon reception of an alarm signal to temporarily stop a semiconductor manufacturing process